To bring ecological functions of upland red soil into full play and screen out better maize cropping systems, a study was carried out making full use of the data accumulated in the recent 23 years of field experiments and analyzing production, energy flow, value flow and integrated utilization/cultivation functions of 15 different maize cropping systems in the soil. Comprehensive evaluation of the cropping systems was performed on the basis of 13 indexes of ecological benefit, economic benefit and social benefit by means of Grey relation degree. Three maize cropping systems were screened out to be optimal and fit for extension on upland red soil. Results shows that the grey relation degree of the ecological benefit and social benefit of Treatment X (pea/early maize + upland rice/late maize) reached 0.750 and 0.986, respectively, ranking first among the 15 and of economic benefit got to 0.841, ranking second. And the treatment was the highest in weighed grey relation degree and hence assumed to be the priority system for extension in the red soil regions in South China. Treatment XI (pea/cotton + early maize) and Treatment XII (Chinese milk vetch—early maize—sesame) followed, being 0.739 and 0.716 in weighed grey relation degree, and would have important roles in optimizing the cropping systems in the upland red soil.